JP2023122868A - solenoid - Google Patents

Abstract

To provide a solenoid capable of appropriately forming a cavity between a movable core and a stationary magnetic pole and maintaining the cavity.SOLUTION: A solenoid comprises: a stationary magnetic pole; a lid member disposed separately from the stationary magnetic pole in an axial direction; a guide pipe which has a structure holding a cylindrical member consisting of a nonmagnetic material between two cylindrical members consisting of a magnetic material and has one end linked to the stationary magnetic pole and the other end linked to the lid member; a coil disposed at an outer peripheral side of the guide pipe; a movable core which is stored in the guide pipe and movable in the axial direction; and a nonmagnetic ring. The stationary magnetic pole includes a first end face opposed to the movable core and an annular protrusion protruding from the first end face outside of the first end face. The movable core includes a second end face opposed to the first end face and an annular step lower than the second end face outside of the second end face. The nonmagnetic ring is held between a protruding end of the annular protrusion and a step face of the annular step, and a cavity is formed between the first end face and the second end face.SELECTED DRAWING: Figure 1

Description

The present invention relates to solenoids.

Electromagnetic valves called solenoids are generally used for fluid flow control and the like. Patent Literature 1 listed below describes a counterbalance valve composed of a solenoid and a pilot section. The solenoid described in Patent Document 1 includes a tubular guide pipe having a structure in which a non-magnetic material is sandwiched between two magnetic bodies, a coil arranged on the outer peripheral side of the guide pipe, and a magnetic body housed inside the guide pipe. and fixed magnetic poles and lid members arranged at both ends of the movable core.

The solenoid supplies a current to a coil arranged on the outer periphery of the guide pipe to form a magnetic circuit between the guide pipe and the movable core. By controlling the current, the position of the movable core is controlled and connected to the movable core. move the rod, thereby controlling the valve.

The moving core and the fixed pole are separated by an airgap. This is to avoid the movable iron core and the fixed magnetic pole being strongly attracted to each other and the position of the movable iron core becoming uncontrollable. A non-magnetic spacer is generally inserted to form this gap (see, for example, Patent Document 2).

U.S. Patent No. 10437269 WO2018/062396

However, due to reasons such as magnetic properties, there are cases where the minimum distance between the movable core and the fixed magnetic pole must be less than, for example, about 0.5 mm. In that case, the non-magnetic spacer mentioned above needs to be very thin. There is a problem that it is impossible to maintain the gap between

SUMMARY OF THE INVENTION An object of the present invention is to provide a solenoid that can properly form an air gap between a movable iron core and a fixed magnetic pole and maintain the air gap.

The solenoid of the present invention includes a fixed magnetic pole made of a cylindrical member made of a magnetic material,
a cover member arranged apart from the fixed magnetic pole in the axial direction;
A guide having a structure in which a cylindrical member made of a non-magnetic material is sandwiched between two cylindrical members made of a magnetic material, one end of which is connected to the fixed magnetic pole and the other end of which is connected to the lid member. a pipe;
a coil arranged on the outer peripheral side of the guide pipe;
a movable iron core housed in the guide pipe and axially movable coaxially with the fixed magnetic pole;
A non-magnetic ring made of a non-magnetic material and arranged between the fixed magnetic pole and the movable iron core,
The fixed magnetic pole has a first end face facing the movable iron core and an annular protrusion projecting outside the first end face beyond the first end face,
The movable iron core has a second end face facing the first end face, and an annular stepped portion located outside the second end face and lower than the second end face,
The non-magnetic ring is sandwiched between the projecting end of the annular protrusion and the stepped surface of the annular stepped portion to form a gap between the first end surface and the second end surface.

According to this configuration, by adjusting the sizes of the annular protrusion, the annular stepped portion, and the non-magnetic ring, it is possible to appropriately form the gap between the first end surface and the second end surface. In addition, according to this configuration, the thin non-magnetic spacer arranged between the first end surface and the second end surface, for example, does not crack or deform, so that the formed air gap can be maintained.

In the solenoid of the present invention, the non-magnetic ring may be fitted to the inner wall surface of the annular stepped portion.

According to this configuration, the non-magnetic ring moves together with the movable iron core while being fitted in the annular stepped portion, so that rattling of the non-magnetic ring can be suppressed. Also, according to this configuration, it is easy to assemble the non-magnetic ring.

In the solenoid of the present invention, the outer peripheral surface of the non-magnetic ring may be separated from the inner peripheral surface of the guide pipe.

According to this configuration, the non-magnetic ring does not come into contact with the guide pipe when the movable iron core moves inside the guide pipe. It can prevent you from getting hurt.

In the solenoid of the present invention, the projecting end of the annular protrusion and the stepped surface of the annular stepped portion may be formed on flat surfaces orthogonal to the axial direction.

According to this configuration, since only the compressive load in the axial direction is applied to the non-magnetic ring, deformation of the non-magnetic ring can be suppressed.

In the solenoid of the present invention, the first end surface and the second end surface may be flat surfaces parallel to each other.

According to this configuration, it is easy to obtain appropriate magnetic characteristics (attractive force curve).

In the solenoid of the present invention, the area of the annular protrusion may be 50% or less of the area of the first end surface when viewed from the axial direction.

According to this configuration, by providing the annular protrusion and the annular stepped portion, it is possible to control the suction force curve to an appropriate shape.

1 is a vertical sectional view of a solenoid according to one embodiment of the present invention; Vertical cross-sectional view showing part of the solenoid in FIG. Enlarged view of area III in Fig. 2 Longitudinal cross section of fixed magnetic pole Longitudinal cross-sectional view of lid member Longitudinal cross-sectional view of guide pipe, movable iron core, and rod

An example of an embodiment of the solenoid of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an example of a solenoid. 2 is a longitudinal sectional view showing part of the solenoid in FIG. 1, and FIG. 3 is an enlarged view of the III area in FIG. The solenoid 1 is arranged along the axis L. As shown in FIG. In the following description, the direction parallel to the axis L is called the axial direction D1, the radial direction of a circle centered on the axis L is called the radial direction D2, and the direction along the circle centered on the axis L is called the circumferential direction. Further, the axial direction D1 may be defined with reference to the solenoid 1. For example, the direction in which the rod 9 moves away from the solenoid 1 is called the forward direction, and the direction in which the rod 9 approaches the solenoid 1 is also called the rearward direction. That is, in each figure, the direction of the arrow in the axial direction D1 is also referred to as the forward direction, and the direction opposite to the direction of the arrow in the axial direction D1 is also referred to as the rearward direction.

A solenoid 1 includes a fixed magnetic pole 2 , a lid member 3 , a guide pipe 4 , a coil 5 , a movable iron core 6 , a non-magnetic ring 7 and a case 8 . Solenoid 1 further comprises a rod 9 .

4 is a longitudinal sectional view of the fixed magnetic pole 2. FIG. The fixed magnetic pole 2 is formed with a through hole 2a through which the rod 9 is inserted. The through hole 2a has a cylindrical shape centered on the axis L. As shown in FIG. That is, the fixed magnetic pole 2 is a substantially cylindrical member with the axis L as the center.

The fixed magnetic pole 2 has a rear end face 2b (corresponding to a first end face) facing the movable core 6, and an annular protrusion 21 projecting outside the rear end face 2b beyond the rear end face 2b. The rear end face 2b is annular. The annular protrusion 21 protrudes rearward from the rear end surface 2b. Moreover, the annular protrusion 21 has an inner peripheral surface 21a and a protruding end 21b. The inner peripheral surface 21 a surrounds a portion of the movable core 6 . The projecting end 21b is positioned rearward of the rear end surface 2b. The projecting end 21b is formed on a flat surface perpendicular to the axial direction D1.

The annular protrusion 21 has a cylindrical shape with a constant thickness in the radial direction D2 over the entire circumference. The thickness of the annular protrusion 21 in the radial direction D2 is set to 0.3 to 1.5 mm, depending on the size of the solenoid 1 as a whole and the pressure in the operating environment. If the thickness of the annular protrusion 21 in the radial direction D2 is within this range, deformation of the annular protrusion 21 can be prevented.

When viewed from the axial direction D1, the area of the annular protrusion 21 (the area of the projecting end 21b) needs to be set according to the size of the solenoid 1, the pressure in the operating environment, the required suction force curve, and the like. is, for example, preferably 50% or less of the area of the rear end face 2b, and more preferably 25% or less. By adjusting the ratio of the area of the rear end surface 2b and the area of the annular protrusion 21, the suction force curve can be controlled to have an appropriate shape. The area of the rear end face 2b is the area of the ring excluding the through hole 2a.

A recess 2d is formed at the rear end of the outer peripheral surface 2c of the fixed magnetic pole 2. As shown in FIG. The recess 2d is formed along the entire circumference of the fixed magnetic pole 2, and the guide pipe 4 is fitted therein.

The fixed magnetic pole 2 is made of a magnetic material. As the material of the fixed magnetic pole 2, carbon steel having a low carbon content is preferable, and iron materials in general such as S10C can be used.

FIG. 5 is a longitudinal sectional view of the lid member 3. As shown in FIG. The lid member 3 is a substantially cylindrical member centered on the axis L. As shown in FIG. That is, the lid member 3 is arranged coaxially with the fixed magnetic pole 2 . Also, the lid member 3 is arranged apart from the fixed magnetic pole 2 in the axial direction D1.

The lid member 3 has an annular connecting portion 31 projecting forward. A rear end of the guide pipe 4 is connected to the connecting portion 31 . An inner peripheral surface 31a of the connecting portion 31 is flush with the inner peripheral surface 4a of the guide pipe 4 (see FIG. 2).

The lid member 3 is made of a non-magnetic material. Non-magnetic stainless steel such as SUS304 can be used as the material of the lid member 3 . However, the lid member 3 may be made of a magnetic material because it has little effect on the magnetic properties.

FIG. 6 is a longitudinal sectional view of the guide pipe 4, movable iron core 6, and rod 9. As shown in FIG. The guide pipe 4 has a structure in which a cylindrical member made of a non-magnetic material is sandwiched between two cylindrical members made of a magnetic material. In this embodiment, the guide pipe 4 has a structure in which a non-magnetic pipe 43 is sandwiched between the first magnetic pipe 41 and the second magnetic pipe 42 from both sides in the axial direction D1. The first magnetic pipe 41, the second magnetic pipe 42, and the non-magnetic pipe 43 are arranged coaxially with each other. Also, the guide pipe 4 is arranged coaxially with the fixed magnetic pole 2 .

The thicknesses of the first magnetic pipe 41, the second magnetic pipe 42, and the non-magnetic pipe 43 are all the same, and the guide pipe 4 has a cylindrical shape with a uniform thickness as a whole. The thickness of the guide pipe 4 is, for example, 0.3-2.5 mm.

The first magnetic pipe 41 and the second magnetic pipe 42 are made of a magnetic material such as S10C. Also, the non-magnetic pipe 43 is made of a non-magnetic material such as SUS304. The first magnetic pipe 41 and the second magnetic pipe 42 are diffusion-bonded to the non-magnetic pipe 43 .

The guide pipe 4 has one end 4b connected to the fixed magnetic pole 2 and the other end 4c connected to the lid member 3 . Specifically, the first magnetic pipe 41 is welded to the recess 2 d of the fixed magnetic pole 2 , and the second magnetic pipe 42 is welded to the connecting portion 31 of the lid member 3 .

The coil 5 is arranged on the outer peripheral side of the guide pipe 4, as shown in FIG. A coil 5 surrounds part of the fixed pole 2 and part of the guide pipe 4 . Also, the coil 5 is covered with a case 8 . The solenoid 1 is configured such that the movable iron core 6 moves in the axial direction D<b>1 while being guided by the inner peripheral surface 4 a of the guide pipe 4 by applying a current to the coil 5 .

The coil 5 includes a bobbin 51 , a coil wire 52 and an outer mold 53 . The bobbin 51 has a substantially cylindrical body portion and flanges formed at both ends of the body portion in the axial direction D1. A coil wire 52 is wound on the body portion of the bobbin 51 between the two flanges. A control device (not shown) is connected to the coil wire 52 to allow a controlled current to flow. The outer mold 53 accommodates the coil wire 52 together with the bobbin 51 .

The movable core 6 is accommodated in the guide pipe 4 and moves coaxially with the fixed magnetic pole 2 in the axial direction D1. The movable iron core 6 is formed in a substantially cylindrical shape with the axis L as the center. An outer peripheral surface 6 a of the movable iron core 6 slides on an inner peripheral surface 4 a of the guide pipe 4 .

The movable iron core 6 has a front end face 6b (corresponding to a second end face) and an annular stepped portion 61 outside the front end face 6b that is lower than the front end face 6b. The front end face 6 b faces the rear end face 2 b of the fixed magnetic pole 2 . The front end face 6b is disc-shaped and has substantially the same outer diameter as the rear end face 2b.

The annular stepped portion 61 is formed by notching the front end of the outer peripheral surface 6a of the movable iron core 6 . The annular protrusion 21 of the fixed magnetic pole 2 is inserted into the annular stepped portion 61 .

The annular stepped portion 61 has an inner wall surface 61a and a stepped surface 61b. The inner wall surface 61a faces the inner peripheral surface 21a of the annular projection 21 with a gap therebetween. The step surface 61b is positioned rearward of the front end surface 6b. The step surface 61b faces the projecting end 21b of the annular projection 21. As shown in FIG. The step surface 61b is formed as a flat surface perpendicular to the axial direction D1.

A non-magnetic ring 7 is arranged between the fixed magnetic pole 2 and the movable core 6 . Specifically, the non-magnetic ring 7 includes the projecting end 21b of the annular protrusion 21, the inner wall surface 61a of the annular stepped portion 61, the stepped surface 61b of the annular stepped portion 61, and the inner peripheral surface 4a of the guide pipe 4. placed in a space surrounded by The non-magnetic ring 7 is fitted to the inner wall surface 61 a of the annular stepped portion 61 and moves together with the movable core 6 .

The non-magnetic ring 7 is sandwiched between the projecting end 21b of the annular protrusion 21 and the stepped surface 61b of the annular stepped portion 61, and is positioned between the rear end surface 2b of the fixed magnetic pole 2 and the front end surface 6b of the movable core 6. A gap G (see FIG. 3) is formed. Thus, the non-magnetic ring 7 positions the movable core 6 with respect to the fixed magnetic pole 2 . The gap G is set to 0.1 to 0.5 mm, for example.

The non-magnetic ring 7 is formed in a cylindrical shape. The outer peripheral surface of the non-magnetic ring 7 is separated from the inner peripheral surface of the guide pipe 4 . The non-magnetic ring 7 has a thickness greater than the clearance between the inner peripheral surface 21 a of the annular protrusion 21 and the inner peripheral surface 61 a of the annular stepped portion 61 so as not to fit between the annular protrusion 21 and the annular stepped portion 61 . The magnetic ring 7 is set to be less than the width of the annular stepped portion 61b so that the magnetic ring 7 does not act as a sliding resistance, and the thickness of the cylinder is formed to be 0.3 to 1.4 mm, for example. The height of the non-magnetic ring 7 is set according to the attractive force curve shape and the moving distance (stroke) of the movable iron core 6, and is formed to be 1.0 to 3.0 mm. The non-magnetic ring 7 of this embodiment is formed to have a cylindrical thickness of 0.7 mm and a height of 1.3 mm.

The non-magnetic ring 7 is made of a non-magnetic material. Nonmagnetic stainless steel such as SUS304 can be used as the material of the nonmagnetic ring 7 .

The case 8 is located on the outer peripheral side of the coil 5 and covers the coil 5, as shown in FIG. A case 8 is fixed to the fixed magnetic pole 2 and the guide pipe 4 .

The rod 9 is always pressed against the front end face 6b of the movable iron core 6 by, for example, a spring (not shown). Thereby, the rod 9 moves in the axial direction D1 together with the movable iron core 6 . The rod 9 is inserted through the through hole 2 a of the fixed magnetic pole 2 .

It should be noted that the solenoid 1 is not limited to the configuration of the embodiment described above, nor is it limited to the effects described above. Further, it goes without saying that the solenoid 1 can be modified in various ways without departing from the gist of the present invention. For example, each configuration, each method, etc. of the plurality of embodiments described above may be arbitrarily adopted and combined, and further, one or more of the configurations, methods, etc. according to the various modifications described below may be arbitrarily selected. , of course, may be employed in the configurations, methods, and the like according to the above-described embodiments.

In the solenoid 1 according to the above embodiment, the non-magnetic ring 7 is fitted to the inner wall surface 61 a of the annular stepped portion 61 . However, the solenoid 1 is not limited to such a configuration. The non-magnetic ring 7 may be fitted to the inner peripheral surface 4 a of the guide pipe 4 . At this time, the inner peripheral surface of the non-magnetic ring 7 is preferably separated from the inner wall surface 61 a of the annular stepped portion 61 .

DESCRIPTION OF SYMBOLS 1... Solenoid, 2... Fixed magnetic pole, 2a... Through hole, 2b... Rear end face (first end face), 2c... Outer peripheral face, 2d... Recessed part, 3... Lid member, 4... Guide pipe, 4a... Inner peripheral face, 4b One end 4c Other end 5 Coil 6 Movable iron core 6a Outer peripheral surface 6b Front end surface (second end surface) 7 Non-magnetic ring 8 Case 9 Rod 21 Annular protrusion Parts 21a... Inner peripheral surface 21b... Protruding end 31... Connecting part 31a... Inner peripheral surface 41... First magnetic pipe 42... Second magnetic pipe 43... Non-magnetic pipe 51... Bobbin 52... Coil wire 53 Exterior mold 61 Annular stepped portion 61a Inner wall surface 61b Stepped surface G Gap D1 Axial direction D2 Radial direction L Axial line

Claims (6)

a fixed magnetic pole made of a cylindrical member made of a magnetic material;
a cover member arranged apart from the fixed magnetic pole in the axial direction;
A guide having a structure in which a cylindrical member made of a non-magnetic material is sandwiched between two cylindrical members made of a magnetic material, one end of which is connected to the fixed magnetic pole and the other end of which is connected to the lid member. a pipe;
a coil arranged on the outer peripheral side of the guide pipe;
a movable iron core housed in the guide pipe and axially movable coaxially with the fixed magnetic pole;
A non-magnetic ring made of a non-magnetic material and arranged between the fixed magnetic pole and the movable iron core,
The fixed magnetic pole has a first end face facing the movable iron core and an annular protrusion projecting outside the first end face beyond the first end face,
The movable iron core has a second end face facing the first end face, and an annular stepped portion located outside the second end face and lower than the second end face,
The solenoid, wherein the non-magnetic ring is sandwiched between the protruding end of the annular projection and the stepped surface of the annular stepped portion to form a gap between the first end face and the second end face. 2. The solenoid according to claim 1, wherein said non-magnetic ring is fitted to the inner wall surface of said annular stepped portion. 3. The solenoid according to claim 1, wherein the outer peripheral surface of said non-magnetic ring is separated from the inner peripheral surface of said guide pipe. 4. The solenoid according to any one of claims 1 to 3, wherein the protruding end of said annular protrusion and the stepped surface of said annular stepped portion are each formed on a flat surface orthogonal to said axial direction. 5. The solenoid according to claim 1, wherein said first end surface and said second end surface are flat surfaces parallel to each other. 6. The solenoid according to any one of claims 1 to 5, wherein an area of said annular protrusion is 50% or less of an area of said first end face when viewed from said axial direction.